Strain-tuned enhancement of ferromagnetic T_C to 176?K in Sm-doped BiMnO₃ thin films and determination of magnetic phase diagram.

ABSTRACT: BiMnO₃ is a promising multiferroic material but it's ferromagnetic T_C is well below room temperature and the magnetic phase diagram is unknown. In this work, the relationship between magnetic transition temperature (T_C) and the substrate induced (pseudo-) tetragonal distortion (ratio of out-of-plane to in-plane lattice parameters, c/a) in BiMnO₃ thin films, lightly doped to optimize lattice dimensions, was determined. For c/a?>?0.99, hidden antiferromagnetism was revealed and the magnetisation versus temperature curves showed a tail behaviour, whereas for c/a?C of up to 176?K, more than 70?K higher than for bulk BiMnO₃, was achieved through precise strain tuning. The T_C was maximised for strong tensile in-plane strain which produced weak octahedral rotations in the out-of-plane direction, an orthorhombic-like structure, and strong ferromagnetic coupling.

SUBMITTER: Choi EM 

PROVIDER: S-EPMC5335565 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature